Automatic fuel mixture regulator



Sept. 29, 1931. H.HBNER l AUTOMATIC FUEL MIXTURE REGULATOR Filed Aug.15. 1927 Patented sept. 29, 19314 PATIENT OFFICE HUGO HIIBNER, FMOSBACH, GERMANY AUTOMATIC FUEL MIXTURE REGULATOR Application led'August15, 1927. Serial No. 213,126,

The function of the automatic fuel mix-l ture regulator is so toinfluence the compost tion of the fuel mixture in explosion motors, moreparticularly motor car engines, that for each load of the engine themost favourable mixing ratio of fuel and air is provided. The apparatusenables more particularly the deviations from the most favourablecomposition of the fuel mixture to be equalized,

which deviations are caused by the physical properties of fuel and air(differences in temperature, differences in specific gravity, densityand the like). This correction is of great advantage for the reason thatboth the out-put of the engine and the fuel consumption are therebyfavourably" affected. The variations in the fuel mixture caused by thedifferent loads of the engine are completely automatically equalized,while those produced by physical influences and which occur very rarelyare equalized by manual regulation.

The modern Carburettor has without doubt been brought to a high state ofperi fection. It has become possible so to arrange it that it produces,for each position of the throttle, a mixture, in which the proportion offuel to air is practically constant, and that it is also suitable forgasifying heavy fuels. On the other hand, is not possible to correctwith it the variationsin the composition of the gas mixture caused bythe heating of the engine and by external influence (the height of thebarometer, moist air, temperature, and the like). This explains the factthat a Carburettor which, on starting the engine, delivers a fuelmixture which is perfect as regardsits composition, supplies, after theengine has become hot,

lo a mixture far too rich in fuel, "so that, on the one hand, theconsumption of fuel is far too great and, on the other hand, the powerof the engine drops. This change in the composition of the fuel mixture,on the engine becoming heated, is due to the fact that, on the one hand,the air expands owing to the heating and consequently has less oxygenper unit valume than cold air, and on the other hard the fuel becomesmore liquid through 'he'heating and consequently more and in GermanyAugust 21, 1926.

fuel passes out' of the nozzle in unit time than when in the cold state.Through the new' automatic fuel mixture regulator, a correct compositionof the fuel mixture is produced in an unexceptional manner, as with itas much air is added automatically to the fuel mixture supplied by thecarburettor as is required for forming the correct mixture. Hence, itsuse ensures a great saving in fuel and the highest possible developmentof power by the engine.

Various types of fuel economizers have been proposed, which are intendedto improve the already-made gas mixture by the supply of additional airor to bring it nearer to a correct composition. Some of them arearranged for being regulated by hand and would in this form fulfil theirpurpose, if a fresh regulation was effected each time the engine changesits power, which, however, is usually not done for convenience sake,while others are arranged for automatic working. The latter kind ofconstruction of the existing types of economizers does not sufficientlyallow for the pressure conditions pertaining in the suction, pipe of theengine, and, in

-addition to this, their manner of working and' theiry ability to beregulated are so imperfect that it is rarely worth while introducingthese automatic apparatus.

The new automatic fuel mixture -regulator completely avoids thesedrawbacks and inadequacies of the existing constructions intended forthe same purpose, as it is easily adjustable, it may be adapted to anyengine, and, when once set, works abso-f lutely automatically. Itcommences to function immediately the throttle is opened and becomesautomatically inoperative on the said vthrottle being closed. It addsautomatically to the gas mixture the quantity of additional aircorresponding to each position of the throttle and to each speed ofrevolution of the engine. The apparatus is suitably mounted in thevicinity of the drivers seat on the instrument board, can be put intoand out of operation by a simple manipulation from the drivers seat, andcan be so adjusted that, on driving downhill, it supplies a largequantity of air to the motor for cooling it, with the throttle closed,prevents the consumption of fuel and the sparking plugs from becomingoily, and liberates a certain amount of braking action. The apparatuscan also be'mounted directly on the suction pipe of the engine or byintroducing into the same behind the Carburettor. In this case rodworkor Bowden control for regulating by hand must be provided.

The fuel mixture regulator according to the present invention makes useof the pressure conditions produced in the suction pipe by the suctionaction of the engine with respect to the outside air, which conditionsvary with each fresh setting of the throttle and each time the speed ofrevolution of the engine varies, for displacing automatically a pistonloaded by an opposing spring, such that a slide valve connected to thepiston opens according to the requirements of the engine ports throughwhich the fresh air can flow into the suction pipe and become mixed withthe fuelmixture. A constructional example of the arrangements requiredfor this purpose is shown in the accompanying drawings, in which Fig. 1is a longitudinal section through the regulator which is connected bypipes to the Carburettor, and

Fig. 2 a longitudinal section of a regulator mounted in the suction pipeof an en ne.

igure 3 shows an elevation of the lower end of the pipe through whichthe additional air is admitted to the engine suction pipe, together withan elevation of a tubular rotary valve which is inserted in the pipeforcontrolling the supply of additional air by hand.

The regulator consists of a cylinder a, one end of which is closed andthe -other open. Through the middle of the cylinder end a pipe bextends, which' is concentric with the cylinder and is fixed to the saidcylinder end. In the cylinder a, and tting closely in the same, thereslides the piston c which surrounds the pipe/b so as to be capable ofsliding on it, but so as to iit closely to it. To the piston c is fixedthe sleeve d. At its upper and lower end the said sleeve fits closelyround the pipe?) while the middle part is recessed for preventing toogreat a' friction. At the sliding part where the sleeve d is fixed tothe piston c, an internal annular groove Z is provided, having severalholes m through which it communicates with theouter air. Through aspring k which may be wound cylindrically or conically according torequirements the piston c is lforced towards the open end of thecylinder a. In piace of a cylindrical or conical spring, two or more`springs of different strength maybe provided, inaccordance with therequisite spring pressure at diferent positions of the piston. In thatpart of the pipe b which is covered bv the sleeve d when the apparatusis inoperative, are a number of uniformly distributed holes o of equalor different size, which are distributed over about one-third of itsperiphery along the length of the recessed part of the sleeve el.Instead of one, two or more sets of rows of holes can be provided in thepipe. The pipe b is open at both ends. At one end. the tube e isinserted which" is open at its inner end and terminates at its outer endin a knob by means of which it can be turned about its longitudinalaxis. This tube e is provided with a lateral slot p so that, by turningit, the holes o in the pipe b can be opened or closed row by row.Instead of one slot p two or more slots may be provided according to thenumber of rows of holes provided in the pipe b. The other end of thepipe b is connected by the pipe i (a rigid or flexible pipe) to thesuction pipe of an engine, more particularly to the space 'l' betweenthe throttle g and the suction valve. The cylinder a is connected by thebranch g and the pipe h to that part of the Carburettor s whichliesbetween the atomizer t (constriction of the Carburettor at thenozzle opening) and the throttle g. Over the open end of the cylinder aa sieve cap f is mounted which also surrounds the pipe b. The apparatuscan be fixed by means of the flange n to the instrument board or anyother suitable place. If the tube b be widened, as shown in Fig. 2, theapparatus may also be mounted behind the carburettor directly in thesuction pipe of the engine. The pipe i is not required in this case andthe pipe h becomes very short. For operating the tube c a lever uextends to the outside.

As stated above, the principle of the automatic fuel mixture regulatoris based on the utilization of the differences in pressure according tothe various parts of the pipe of the engine. The suction pipe may bedivided into three zones, each of which has a different pressure. Thefirst zone extends from the lower end of the carburettor to the middleof the atomizer. In this zone the external air pressure usuallyprevails. There will only be a certain amount of partial vacuum when theengine is working under full load. The second zone extends from themiddle of the atomizer to the throttle. l`Vl7hen the engine is workingwith the throttle almost closed, there will be no vacuum in this part,as only a small amount of air is withdrawn by suction and sufficient aircan flow in through the Carburettor opening. When, however, the throttleis opened further, a vacuum will be formed which becomes greater andgreater the further the throttle opened, as the cross sectional areaofthe -suction pipe is reduced by the atom? izer of the Carburettor andunder ordinary air pressureas much air cannot i'low through the'atomizer as is; aspired by the engine. Thethird zone extends from thethrottle to the suction valves. Here, owing to Athe suction action ofthe lengine when the throttle is closed, a considerable vacuum prevailswhich becomes less and less as the throttle is opened and when thethrottle is quite opened becomes equal to the vacuum in the second zone.

The automatic fuel mixture regulator is connected to the engine by twoseparate pipes. One connection is established between the branch of thepipe b, extending out of the apparatus, and the third zone of thesuction pipe, by the pipe z'. The cylinder a is connected by the pipe kwith the second zone. The regulation of the air supply to the fuelmixture is effected as follows: when the engine is running and onopening the throttle, a partial vacuum is formed in .the second zone ofthe suction pipe, the said partial -vacuum will be imparted through thepipe 71, of the branch 0 to the cylinder a where it will act on theApiston c. The piston c will be drawn by suction into the opening of thecylinder, until the pressure .of the spring k balances the suction. Thesleeve d will move with the piston and will expose one ormore transverserows of holes of the pipe b, according to the extent to which thethrottle is opened,

or the amount of partial vacuum. -Air will flow through the opened onesinto the interior of the pipe b and will be drawn strong- 1y by suctionthrough the pipe z by the engine to the suction pipe of thefsame, owingto the considerable vacuum prevailing there, where it will mix with thefuel mixture. The further the throttle is opened, the greater will bethe partial vacuum and the greater will be the number of rows of holesexposed until, when the throttle is entirely opened,

`all the holes will be exposed. 0n the throttle being closed again, thepartial vacuum within the cylinder a will disappearl again,

andthe spring la will force the piston c with the sleeve d immediatelyback into the viliperative position, thus causing the air supo p y tocease. The partial vacuum in the Carburettor (between the atomizer andthe throttle) besides being infiuenced by the amount to which thethrottle is opened, is also influenced by the speed of revolution of theengine. The automatic apparatus makes allowance for this circumstance aswell. When the engine is running at a high speed, more fuel is drawn inby suction, the vacuum becomes greater and the automatic apparatusprovides a correspondingly greater quantity of air. Thus it regulatesthe supply ofadditional air in an ideal manner.

By means of the slide in the tube e by turning the latter as manylongitudinal rows of holes may be exposed for the admission of air asthe degreeof saturation ofthe fuel mixture supplied by the atomizerallows. This degree of saturation depends on the size of the fuelnozzle, whether the engine is cold or hot, whether the outer air is coldor warm and so on. All these contingencies can be" equalized by simplyturning the tube e. If the tube e be partially or entirely withdrawnfrom the pipe b, the entire air opening is exposed and the entirequantity of air, which the cross sectional area of the pipe b will allowto pass through, will low to the engine. W'hen the throttle is closed,for instance, when driving downhill, the engine will consequently aspireonly fresh air. This will iirstly cool the engine, secondly prevent thesparking plugs .becoming oily as the vacuum in the cylinder is reduced,thirdly, save fuel for the same reason and fourthly produce a brakingaction on the car. When the engine is not running, by opening the pipeb, any unauthorized person is prevented from starting the engine as noexplosible gas mixture can be formed owing to the whole amount ofadditional air flowing in;

The provision of the smaller groove Z and the holes m is' intended toprevent the partial vacuum between the sleeve d and the pipe b beingcommunicated to ythe space within the cylinder a and the function of thepiston c being interfered with. This is effected by any particles of air-drawn by suction between the sleeve and the pipe being taken out fromthe space in the cylinder a but through the holes m from the outsideair.

It is not necessary for the air te be supplied centrally with thetubular slide surrounding the air pipe and the piston.

These two parts can be separated or a Vfiat slide may be provided on oneside only.

lVhat I claim is:

1. An apparatus for regulating the supply of additional air tothesuction pipe of an explosion motor, comprising the combination with thesuction pipe and a throttle therein, of an air pipe having a pluralityof rows of holes therein at one end and connected to thesuction pipe onthe engine side of the throttle, a cylinder in open communication at oneend with the suction pipe lon the atmospheric side of the throttle andsurrounding said air pipe, said cylinder being closed at the end thereof1n open communication with the suction pipe and openi at the oppositeend and an assembly comprising a regulating piston and a sleeveconnected to said piston, so as to be movable in unison therewithmounted' on the air pipe so asl to be slidable thereon with theregulating piston movable in the cylinder by the variation in pressurein the suction pipe on` the atmospheric side of the throttlev and thesleeve adapted to cover and uncover with its end remote from theregulating piston, the said holes in the air pipe for regulating thesupply of air to the air pipe, said sleeve being recessed intermediatelyof its ends and having at the junction of the pistorf and sleeve aninternal annular groove and holes in its wall communicating with theoutside and said groove, a rotary sleeve in the air inlet pipe, saidsleeve having air regulating openings ada ted to co-operate with theopenings in t e air inlet pipe and. means connected to said sleeve forturning the sleeve by hand for varying the number of holes uncovered bythe sleeve from the outside, as and for the purposes set forth.

2. An apparatus for regulating the supply of additional air to thesuction pipe of an explosion motor, comprising the combination with thesuction pipe and a throttle therein, of an air pipe having air inletopenings therein and interposed in the suct1on pipe on the engine sideof the throttle so as to form an intermediate part of the suction pipe,a cylinder in open communication 'at one end with the suction pipe onthe atmospheric side of the throttle and surrounding said air pipe, saidcylinder being closed at the end thereof in open communication with thesuction pipe and open at the opposite end, an assembly comprising aregulating piston and a sleeve connected v to said piston, so as to bemovable in unison therewith, mounted on the air pipe so as to beslidable thereon with the regulating piston movable in the cylinder bythe variation in pressure in the suction pipe on the atmospheric side ofthe throttle and the sleeve adapted to cover and uncover with its endremote from the regulating piston the said air inlet openings in the airpipe for regulating the supply of air to the air pipe in accordance withthe suction produced on the atmospheric side of the throttle, the sleevebeing recessed intermediately of its ends, and a rotary sleeve open atboth ends, in the air inlet pipe, said sleeve having air regulatingopenings adapted to co-operate with the openings in the air inlet pipe.

3. An apparatus for regulating the supply of additional air to thesuction pipe of an explosion motor, comprising the combination with thesuction pipe and a throttle therein, of an air pipe havin air inletopenings therein and interpose in the suction pipe on the engine side ofthe throttle so as to form an intermediate park of the suction pipe, acylinder in open communication at one end with the suction pipe on theatmospheric side of the throttle and surrounding said air pipe, saidcylinder being closed at the end thereof in open communication with thesuction pipe and open at the opposite end, an assemblycomprising aregulating piston and a sleeve4 connected to said piston, sok as to bemovable in unison therewith, mounted on the air pipe so as to beslidable thereon with the regulating piston movableA in the cylinder bythe variation in pressure inthe suction pipe on the atmospheric side ofthe throttle and the sleeve adapted to cover and uncover with its endremote from the regulating iston the said holes in the air pipe for reguating the supply of air to the air pipe, said sleeve being recessedintermediately of its ends and having at the junction of the piston andsleeve an internal annular groove and holes in its wall communicatingwith the outside and said groove, a rotary sleeve in the air inletpipe', said sleeve having air regulating openings adapted to co-operatewith the openings inthe air inlet pipe and means connected to saidsleeve for turning the sleeve by hand for varying the number of holesuncovered by the sleeve from the outside, as and for the purposes setforth.

In testimony whereof I have signed my name to this specification.

HUGO HUBNER.

